Pipeline corrosion, material failure and aging facilities are the major safety-related problems that pipelines and local distribution companies face.
With efforts by pipelines and state regulators, the Pipeline and Hazardous Safety Administration (PHMSA) said it anticipates a significant reduction in pipeline-related deaths or major injuries over the next four years.
“By 2016, we aim to reduce the number of pipeline incidents involving death or major injury to between 26 and 37 per year [and] reduce the number of hazardous materials incidents involving death or major injury to between 21 and 32 per year,” said the Department of Transportation’s PHMSA Strategic Plan for 2012-2016.
With respect to pipelines, some of the key challenges to be faced over the next five to 10 years will be changes in risk exposure; aging/obsolete infrastructure; excavation and other outside force damage to pipes; and corrosion and material failure, the agency said. “Most of the macro indicators related to risk exposure are expected to increase. The most important of these factors are population growth, energy consumption and chemical production.
“Risk exposure is generally a function of population times the amount of hazard present. Forecasts of these indicators from the Department of Energy suggest that we might see a 13-27% increase in risk exposure from 2011-2015,” PHMSA said in its plan. “Population growth is nearly certain. Economic growth projections…are much more uncertain.”
PHMSA requires pipelines to employ strict safety measures in highly populated areas. “Pipeline operators must consider population exposure in implementing their integrity management programs and in classifying natural gas transmission lines. High-population areas are subject to more rigid technical requirements and inspections,” the agency said.
To illustrate the dangers associated with aging, high-risk pipelines, PHMSA cited the explosion in February 2011 of an 83-year-old cast iron gas main in Allentown, PA, that resulted in five deaths and set fire to a block of homes (see Daily GPI, Feb. 11, 2011).
“Nearly 450,000 miles of natural gas and hazardous liquid pipelines (about 17% of the total) are over 50 years [old] or of unknown vintage; 168,000 miles of gas distribution pipelines (8% of the distribution mileage in the U.S.) were built with bare steel, iron, copper or ‘other’ materials. These materials are more vulnerable to deterioration and failure than most of the plastic or protected steel materials commonly used today.
“Moreover, the condition of distribution pipelines is often unknown. Virtually all of the gas distribution pipelines are buried underground, and most are inaccessible by internal inspection devices (pigs). States widely acknowledge the need to replace bare steel and cast iron pipeline, but replacement programs extend up to 100 years in some cases, with high replacement costs,” PHMSA said.
PHMSA proposes to work with state safety programs and pipeline operators to ensure that the identification, repair, rehabilitation, requalification or replacement of the highest-risk pipelines are accelerated; extend the pipeline integrity management program to gas distribution pipeline systems, where 80% of the most serious safety incidents occur; and investigate new technologies to improve the assessment, detection and control of pipeline risks.
PHMSA said it also plans to enhance its “811 — Call Before You Dig” program to reduce the number of deaths or injuries related to excavation or other outside force damage to pipelines.
The agency said pipeline corrosion and material failure are the two leading causes of pipeline incidents overall, particularly for natural gas transmission and hazardous liquid lines. It cited two examples of such failures: the September 2010 rupture and explosion on the Pacific Gas and Electric pipeline in San Bruno, CA, which killed eight people (see Daily GPI, Sept. 13, 2010); and the 2010 rupture and spill of Enbridge Energy Partners LP’s oil pipeline in the Kalamazoo River in Marshall, MI.
In its report on the Enbridge incident, the National Transportation Safety Board said it was the most expensive oil spill in U.S. history, spilling more than 840,000 gallons into hundreds of acres of Michigan wetlands (see Daily GPI, July 16).
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